"Dropdown" component - Add support for "LinkToExternal" engine component (08)

[didoo]

📌 Summary

This is a draft PR to discuss (using real code) a possible solution to the problem of supporting LinkToExternal links in our components (these are very special kind of links, similar to the <LinkTo> but specific for Ember engines.

More context:

• https://github.com/hashicorp/cloud-ui/pull/2362#issuecomment-1097909966
• https://hashicorp.slack.com/archives/CPB8GS9QT/p1649868202616679

👉 Notice: if you want to test it yourself and play with the code:

• clone the repo, then do a yarn install in the root of the project, and then call yarn start in the folder packages/components
• this will build the dev version of the dummy website and run it as localhost (you will see the port in the CLI)
• open the localhost website and navigate to the Dropdown page

🛠️ Detailed description

In this PR I have:

• added ember-engines as both devDependency and peerDependency
  • as suggested by Matthew Irish in this conversation in Slack
  • we need both according to the documentation
• updated the list-item/interactive to support also a LinkToExternal via a @isRouteExternal prop
• changed one of the routes in the dropdown doc page to use an external route

🚨 Notice: this triggers an error in console, I suspect we need to configure the app to support engines

I am not sure how to proceed from here, is beyond my Ember knowledge.

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💬 Please consider using conventional comments when reviewing this PR.

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  • https://app.asana.com/0/0/1202122650634755

[changeset-bot]

🦋 Changeset detected

Latest commit: 084a1a4

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@hashicorp/design-system-components	Patch

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[MelSumner]

Are we sure that we need to add ember-engines as a peer dependency? This seems strange to me. Engines should be able to consume and use the addon w/o us specifically adding it, shouldn't they?

[didoo]

@MelSumner this is is still in draft because likely will be solved (if approved) by #216

[MelSumner]

Apologies for not getting to this sooner, if we need to ship this to support engines then we should ship it.

[didoo]

closing this one, since it will be fixed by #216 and #217